1. Field of the Invention
The present invention relates to a transmitting unit, and more particularly to a transmitting unit using bearings and the eccentric principle to reduce or increase the rotational speed.
2. Description of the Prior Art
Conventionally, a transmitting unit reducing the rotational speed, which has been industrially used, reduces or increases the rotational speed of the input shaft mainly by disposing gears. The transmitting unit mainly uses worm gears or epicyclical trains, and examples of the transmitting unit are disclosed in Japanese Patent Laid-open No. Sho 60-91043 and Japanese Patent Laid-open No. Sho 63-214542 for further details.
However, since the aforementioned transmitting unit uses relative movement of meshed gears, much power is lost and much noise and vibration is generated. Beyond that, the transmitting unit is mainly used for heavy load. Furthermore, the structure of the transmitting unit is so complicated that it is hard to install the unit, and an output shaft is reversibly rotated when an input shaft is rotated.
In order to settle the aforementioned problems, U.S. Pat. No. 4,736,654 allowed to Zhu S. Ren and entitled xe2x80x9ctransmitting unitxe2x80x9d discloses a transmitting unit reducing speed that uses bearings.
According to the transmitting unit of Ren, an eccentric sleeve and bearings are rotated to push transmitting rods, when an input shaft is rotated. In addition, rolling members that are linearly moved in a radial direction on the outer sides of the transmitting rods are moved along the waves of an outer race.
By the aforementioned operation, the rotational speed of an output shaft mounted to the transmitting race is reduced, and the output shaft is rotated in the same rotational direction as that of the input shaft.
However, the structure of the transmitting unit has a disadvantage in that it is complicated and many parts are required to assemble the transmitting unit. Furthermore, the transmitting unit cannot be easily manufactured. Namely, the transmitting unit is rather an ideal unit.
The present invention has been made to solve the aforementioned problem, and accordingly it is an object of the present invention to provide a transmitting unit that has an integrally formed transmitting race, an integrally formed outer race, and an input shaft in which an eccentric portion is integrally formed therewith, without using a separate eccentric sleeve so as to increase the strength of the unit and minimize the unit.
It is another object of the present invention to provide a transmitting unit that is precisely maintained and decreases the noise and the vibration thereof during the operation of the unit.
In order to achieve the aforementioned objects of the present invention, the present invention provides a transmitting unit comprising an input shaft driven by a driving device; a sleeve driven together with the input shaft when the input shaft is driven and having a first concentric portion, a second concentric portion, and an eccentric portion; a first bearing assembled along the outer periphery of the first concentric portion; a second bearing assembled along the outer periphery of the second concentric portion; a third bearing assembled along the outer periphery of the eccentric portion and strangely enough moving when the input shaft is driven; an integrally formed transmitting race having a first flange surrounding the outer periphery of the first bearing, a second flange surrounding the outer periphery of the second bearing, and a third flange surrounding the outer periphery of the third bearing and integrally formed with the first and second flanges, the third flange having a plurality of radial holes spaced apart at a predetermined distance; the same plurality of transmitting rods respectively inserted into the radial holes of the third flange of the transmitting race; an integrally formed outer race located out of the transmitting race and having a plurality of wave grooves on the inner periphery thereof; and the same plurality of balls respectively provided between the transmitting rods and the wave grooves of the outer race in order to roll on the wave grooves.
According to one aspect of the present invention, the sleeve is integrally formed with the input shaft.
According to the other aspect of the present invention, the first to third bearings are ball bearings, and the transmitting rod has a circular cross-section.
Preferably, a semi-spherical recess is formed on one side of each transmitting rod so that the corresponding ball is positioned in the recess.
Preferably, the same plurality of rollers are respectively provided between the third bearing and the transmitting rods, and a groove is formed on one side of each transmitting rod so that the corresponding roller is positioned in the groove.
Preferably, a pair of fourth bearings is provided between the outer race and the transmitting race, and the fourth bearings are respectively assembled around the first and second flanges of the transmitting race.